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Search: id:A139669
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| A139669 |
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Number of isomorphism classes of finite groups of order 11*2^k, which appears to be the same as the number of such classes of order 19*2^k and conjecturally of order p*2^k for primes p such that p is congruent to 3 mod 4 and p+1 is not a power of 2. |
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1
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OFFSET
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0,2
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COMMENT
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This appears to be the smallest possible number of groups of order n*2^k for an odd number n.
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REFERENCES
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J. H. Conway et al., The Symmetries of Things, Peters, 2008, p. 206.
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LINKS
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John H. Conway, Heiko Dietrich and E. A. O'Brien, Counting groups: gnus, moas and other exotica.
J. H. Conway, Heiko Dietrich and E. A. O'Brien, Counting groups: gnus, moas and other exotica.
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EXAMPLE
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a(2) is the number of groups of order 11*2^2=44, which is 4 and also the number of groups of order 19*2^2=76, 23*2^2=92, etc.
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CROSSREFS
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Sequence in context: A126947 A063179 A096802 this_sequence A039301 A131529 A165901
Adjacent sequences: A139666 A139667 A139668 this_sequence A139670 A139671 A139672
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KEYWORD
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hard,more,nonn
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AUTHOR
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Anthony D. Elmendorf (aelmendo(AT)calumet.purdue.edu), Jun 12 2008
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